Here is the PSAT curve from last year (2010)

Test Preparation SAT Preparation
1

<p><a href="http://professionals.collegeboard.com/profdownload/understanding-psat-nmsqt-scores.pdf%5B/url%5D"&gt;http://professionals.collegeboard.com/profdownload/understanding-psat-nmsqt-scores.pdf&lt;/a&gt;&lt;/p>

<p>You can used this to estimate your scores, as you may already have a good estimate of how many mistakes you have made as per the consolidated answers thread.</p>